The in-flight failure of any engine and/or drive component of an aircraft can be catastrophic. For example, the failure of a drive component of a helicopter may lead to loss of life. While it is true that a failure of an engine component of one engine in a multi-engine airplane may not lead to loss of life, such a failure may be tremendously costly, resulting in unscheduled and expensive maintenance of the aircraft.
In response to concerns relating to such failures, certain governing bodies charged with regulating and overseeing aviation have begun to require the use of Health and Usage Monitoring Systems (HUMS) for various aircraft. In the past, any monitoring of critical components of an aircraft was performed by manual inspection before and after flights. Unfortunately, these manual inspection techniques were, at best, insufficient and were generally only successful in confirming the failure of a critical component.
HUMS represent technologically advanced monitoring systems that can forewarn of the upcoming failure of a component of the engine and/or drive system of an aircraft. Typical HUMS generally comprise a series of sensors and one or more data acquisition systems. The sensors are placed on critical components of the engine and drive systems, and the data acquisition system gathers data relating to the performance of the monitored components. For example, a helicopter HUMS may comprise a series of accelerometers that are placed on various components of the engine and drive system, such as components of the tail gear box, intermediate gear box, tail drive shaft, and main gear box. A data acquisition system gathers vibration data from each of the sensors, and the data may then be analyzed after flight. Based on the known frequency responses of the monitored components, aberrations that are indicative of impending component failures may be noted during analysis. As a result, suspect components can be scheduled for maintenance prior to their failure.
The use of HUMS has dramatically improved the overall safety records of aircraft employing its technology. Reports indicate that HUMS use in aircraft has resulted in high success rates in detecting defects, as well as reductions in check flights, tests, and unscheduled maintenance. Thus, the use of HUMS allows an equipped aircraft to maintain a higher level of safety while increasing its operational readiness. Although beneficial, HUMS generally introduce weight tradeoffs, which ultimately translate into increased costs. In some rotary aircraft cases, every pound of extra weight in a helicopter can translate into approximately a thousand dollars in recurring costs and tens of thousands of dollars in non-recurring costs. Not to mention the cost of the HUMS system itself, which can reach a thousand dollars or more per sensor. Furthermore, the complexity of the aircraft can increase these costs. A typical helicopter HUMS may include more than thirty sensors, each hardwired to a data acquisition system. Additionally, each bulkhead of an aircraft will require through-bulkhead connectors for the sensor wires. Not only do the connectors add cost and weight to the aircraft, but they require increased installation time.
Thus, there is a need for an improved Health and Usage Monitoring System for use in monitoring the health and usage of various components of a vehicle. The improved HUMS should provide accurate monitoring of key components of the vehicle and provide the ability to adapt to changing monitoring needs while providing efficient cost and weight characteristics.